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August 19, 2008

Naturalism's Hot Water

Alvin Plantinga, philosophy professor emeritus from Notre Dame, shows why the basic presuppositions and worldview of the new atheists undermine their claim to hold the rationally superior beliefs about religion:

I believe it's extremely important to see that naturalism itself, despite the smug and arrogant tone of the so-called New Atheists, is in very serious philosophical hot water: one can't sensibly believe it....

[T]his is true on several counts, but here I want to concentrate on just one—one connected with the thought that evolution supports or endorses or is in some way evidence for naturalism. As I see it, this is a whopping error: evolution and naturalism are not merely uneasy bedfellows; they are more like belligerent combatants. One can't rationally accept both evolution and naturalism; one can't rationally be an evolutionary naturalist. The problem, as several thinkers (C. S. Lewis, for example) have seen, is that naturalism, or evolutionary naturalism, seems to lead to a deep and pervasive skepticism. It leads to the conclusion that our cognitive or belief-producing faculties—memory, perception, logical insight, etc.—are unreliable and cannot be trusted to produce a preponderance of true beliefs over false....

The first thing to see is that naturalists are also always or almost always materialists: they think human beings are material objects, with no immaterial or spiritual soul, or self. We just are our bodies, or perhaps some part of our bodies, such as our nervous systems, or brains, or perhaps part of our brains (the right or left hemisphere, for example), or perhaps some still smaller part. So let's think of naturalism as including materialism. And now let's think about beliefs from a materialist perspective. According to materialists, beliefs, along with the rest of mental life, are caused or determined by neurophysiology, by what goes on in the brain and nervous system. Neurophysiology, furthermore, also causes behavior. According to the usual story, electrical signals proceed via afferent nerves from the sense organs to the brain; there some processing goes on; then electrical impulses go via efferent nerves from the brain to other organs including muscles; in response to these signals, certain muscles contract, thus causing movement and behavior.

Now what evolution tells us (supposing it tells us the truth) is that our behavior, (perhaps more exactly the behavior of our ancestors) is adaptive; since the members of our species have survived and reproduced, the behavior of our ancestors was conducive, in their environment, to survival and reproduction. Therefore the neurophysiology that caused that behavior was also adaptive; we can sensibly suppose that it is still adaptive. What evolution tells us, therefore, is that our kind of neurophysiology promotes or causes adaptive behavior, the kind of behavior that issues in survival and reproduction.

Now this same neurophysiology, according to the materialist, also causes belief. But while evolution, natural selection, rewards adaptive behavior (rewards it with survival and reproduction) and penalizes maladaptive behavior, it doesn't, as such, care a fig about true belief....

If evolutionary naturalism is true, then the probability that our cognitive faculties are reliable is also very low. And that means that one who accepts evolutionary naturalism has a defeater for the belief that her cognitive faculties are reliable: a reason for giving up that belief, for rejecting it, for no longer holding it....Evolutionary naturalism, therefore—the belief in the combination of naturalism and evolution—is self-refuting, self-destructive, shoots itself in the foot. Therefore you can't rationally accept it. For all this argument shows, it may be true; but it is irrational to hold it. So the argument isn't an argument for the falsehood of evolutionary naturalism; it is instead for the conclusion that one cannot rationally believe that proposition. Evolution, therefore, far from supporting naturalism, is incompatible with it, in the sense that you can't rationally believe them both.

Comments

It seems to me that this argument works only if you can demonstrate that under materialism, our beliefs can have no influence over our behavior. Because if they CAN, and if there is an advantage to having true beliefs rather than false beliefs, then evolution would favour minds that produced true beliefs over minds that produced false beliefs.

J.P. Moreland and C.S. Lewis both argued that under materialism, the mind can have no causal influence over the brain at all. If Plantinga argued something like that, then I think his argument would be sound.

I hear what you're saying, but, it does miss the point of what Lewis and Plantiga are arguing. The issue is not whether or not "true" or "false" ideas are advantageous. The issue is: if our thoughts are merely the product of the cause-and-effect nexus of materialism, then those thoughts are NOT TRUE OR FALSE; they simply exist as effects from some cause. Lewis makes this point well: that for us to claim something is "true" and something is "false," then are we appealing to an authority that is outside of our sense of right and wrong. We actually believe that there is an objective thing called "right" and "wrong" that we are invoking.

So, if materialism is true, then these words (i.e., "true" and "false") are meaningless. Rather, we should just describe all thoughts like, "beneficial to the species" or "conducive to survival." But, in no way can they be "true" or "false" if they are merely the effects from some cause.

But, if they really do teach us about reality--that there really is something beyond us to which we appeal for right and wrong, then there really are "true" thoughts and "false" thoughts. But, then, as Lewis argues, materialism fails.

You can't have it both ways: You can't say that my thoughts are true or false, and then argue: yeah, but, your thoughts are just part of a neutral universe that is causing things all the time. That is self-refuting, since THAT thought you just had was just part of the natural universe. Hitler and Mother Theresa both had constant thoughts and both must be morally equal.

It doesn't come out in this snippet of Plantinga's but Plantinga does consider the view that beliefs do influence behavior. He argues that if beliefs influence behavior, then the evolutionary naturalist should think that the probability that evolution selected reliable cognitive faculties is still either low or inscrutable. After all, there are many ways in which false beliefs can yield adaptive behavior. For instance, say that Bob the Caveman finds himself face to face with a tiger. Now consider this desire-belief pair: Bob desires to be eaten by the tiger, but (falsely) believes that the best way to be eaten by the tiger is to keep away from it at all costs. This is a false belief that turns out to be very adaptive. It is easy to think of many more such examples, which is why Plantinga doesn't think it's probable that true belief would be selected by naturalistic evolution even if beliefs _do_ influence behavior.

I read the full article that Melinda linked to, and Plantinga does argue that true beliefs have no advantage over false beliefs in promoting survival, and that only behavior matters. Since advantageous behavior can result from false beliefs just as easily from true, evolution cannot be rationally affirmed if we assume materialism. That's a valid argument, I think, but I'm skeptical of the view that if materialism is true and evolution is true, that evolution would not be anymore likely to produce reliable cognitive faculties than unreliable cognitive faculties. The tiger analogies does show that it's possible for a false belief to produce advantageous behavior, but it doesn't show that false beliefs in general are just as advantageous as true beliefs.

David, I think you are confusing Plantinga's argument and Lewis' argument. They are similar, but they are not the same argument.

I spoke about "true" and "false" beliefs because those are the words you used in your comment.

You're right; I mentioned Lewis and Plantiga together only because Plantiga references Lewis. After doing that, Plantiga (above) says:

It leads to the conclusion that our cognitive or belief-producing faculties—memory, perception, logical insight, etc.—are unreliable and cannot be trusted to produce a preponderance of true beliefs over false....

This is not Lewis, per se, since Lewis does not say "preponderance," but that NO thoughts can be considered "true" or "false" since those words assume something outside of cause and effect exists.

So is it fair to say that *if* words like "true" and "false" *assume* something outside of cause and effect, that trueness or falseness is so, independant of the viewers opinion? In other words, to claim trueness is to make a statement about something and if it is indeed true, the viewer has only judged correctly--they didn't make it any more the true by calling it true. Then it might follow that the trueness or falseness of any claim would assume that a standard setter was behind the scenes giving these words meaning. If not, trueness or falseness are only subjective words and really meaningless if their origins[thus value] were in/from the being who is making the judgement.

Today, Sunday Aug. 23, Greg quoted a distinguished professor of genetics at Harvard writing in the New York Times Review of Books that materialism is chosen as a conclusion by scientists even when the evidence points in the opposite direction towards the supernatural. I find the quote very enlightening and would like the whole quote and the reference if you wouldn't mind.
As Greg says, they are loading the deck.

Amy,
Plantingas seems to be making the distinction between evolution and naturalism as being: evolution is a scientific theory; naturalism being a philosophical point of veiw. Is this correct, or am I missing something?

Sorry, I haven't checked this post in a long time. I didn't know people would still read it!

The answer to your question is, "yes." What you have said is precisely one facet of Lewis' argument. When we use words like "true" and "false" we are really pointing to something that is True and False. If not, then those words don't mean anything more than, "that's not conducive to my survival" or "that's what I would not prefer," or whatever.

Now, Lewis was NOT arguing that because of this deduction (people use true and false as a means of appealing to something outside of our experience), it follows that there is a God/god. Rather, it means there is something truly "objective"--beyond human experience alone--to which we are appealing.

Now, for Lewis, it was a short step to say that the most probable next step is to assume that this Law of Morality comes from a Law Giver, or God.

Makes sense to me.
Read his Mere Christianity (first few chapters) and his Miracles.